Article ID: 171668
Article Last Modified on 3/24/2000
APPLIES TO
- Microsoft Visual FoxPro 5.0 Standard Edition
- Microsoft Visual FoxPro 5.0a
This article was previously published under Q171668
SYMPTOMS
When using optimistic table buffering on a table inside a database container (DBC), a shared table remains locked after a table update that occurs within a transaction. This situation prevents other users from updating the table. The behavior occurs when the table is in a DBC, the table update is within a transaction and the buffer mode is optimistic table. The behavior does not happen when the table is free.
RESOLUTION
One resolution is to use free tables instead of tables within a database.
Another option is to check, within the transaction, whether the table is locked (ISFLOCKED() returns True) and if the table is locked, use the UNLOCK command to unlock the table.
A third resolution to perform a REPLACE on more than one record is to put the REPLACE statement within a loop so that the scope of the REPLACE statement affects only a single record.
STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This has been corrected in Visual FoxPro 6.0.
MORE INFORMATION
NOTE: This problem occurs only when the scope of records affected by the REPLACE function is more than one.
Steps to Reproduce Behavior
The following code will demonstrate the behavior:
* Start of the Code
CLEAR
CLOSE DATABASES ALL
SET MULTILOCKS ON
SET SAFETY OFF
SET TALK OFF
* Create the database and table
*********************************************************************
* NOTE: If the table is not in a database the problem does not occur.
* The following line can be removed to verify this behavior.
*********************************************************************
CREATE DATABASE test
CREATE TABLE test (CTest C(10) , NTest I)
INSERT INTO Test VALUES ( "one", 1)
INSERT INTO Test VALUES ( "two", 2)
INSERT INTO Test VALUES ( "three", 3)
INSERT INTO Test VALUES ( "four", 4)
CLOSE DATABASES ALL
USE Test SHARED
=CURSORSETPROP( "buffering", 5) && Optimistic Table Buffering
REPLACE NEXT 2 cTest WITH "test"
BEGIN TRAN
IF NOT TABLEUPDATE( 2, .F., "Test")
? "Failed."
ELSE
? "Committed."
ENDIF
END TRAN
IF ISFLOCKED( "Test")
* UNLOCK in test && Uncomment this line to test the UNLOCK command
? "The table is still locked."
ELSE
? "The table is not locked."
ENDIF
?ISFLOCKED()
* End of the Code
Keywords: kbbug kbfix kbvfp600fix kbprb KB171668
